Diagnostic-Code: smtp; 553 5.7.1 "Sender address rejected: not logged in (in reply to RCPT TO command)"

My YunoHost server

Hardware: VPS bought online
YunoHost version: 11.2.4
I have access to my server : Through SSH | through the webadmin |
Are you in a special context or did you perform some particular tweaking on your YunoHost instance ? : no

Description of my issue

I am trying to send emails from different aliases that I created and when trying to send a message from one of these aliases, I get the following error message:

Undelivered Mail Returned to Sender

This is the mail system at host DOMAIN.TLD.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<contact@bob.com>: host bob.com[IP.IP.IP.IP] said: 553 5.7.1
    <contact@alice.com>: Sender address rejected: not logged in (in reply to
    RCPT TO command)

Reporting-MTA: dns; DOMAIN.TLD
X-Postfix-Queue-ID: B71F724C0A2
X-Postfix-Sender: rfc822; contact@alice.com
Arrival-Date: Wed, 27 Sep 2023 23:40:43 +0200 (CEST)

Final-Recipient: rfc822; contact@bob.com
Original-Recipient: rfc822;contact@bob.com
Action: failed
Status: 5.7.1
Remote-MTA: dns; bob.com
Diagnostic-Code: smtp; 553 5.7.1 <contact@alice.com>: Sender address
    rejected: not logged in

Steps to reproduce are the following:


I think some other people came across this issue before, like here: Suite Erreur SMTP 550 5.1.1 : Recipient address rejected : User unknown in virtual mailbox table - #10 by rodinux and here: Utilisation SMTP du registar? - #10 by tmb but for one, it is partly in french and second, I am not sure if there was a proper solution found.
So maybe I did some wrong configuration, or this is something that could be improved in yunohost, as I think it is a great feature to be able to send and receive mails from different identities/aliases.